The messenger bird

the long version

Nathan's father has been arrested. He works for the Ministry of Defence and is accused of leaking top secret information. But as he is dragged into a police car, he gives Nathan a message. It leads to a riddle, but it's not from Dad. It's from an ex-Bletchley Park employee, Lily Kenley, and was written in 1940. Nathan begins to follow the clues left behind by Lily. But how can this war-time story link to his father's fate? Hope for Dad's appeal is fading fast. He must solve the puzzle. Time is running out.